Conventionally, there is known a technique of operating a device by using power obtained by conversion by an energy conversion apparatus (for example, a solar cell) that converts energy other than electricity into power (electrical energy). With such a technique, the surplus of power obtained by conversion by an energy conversion unit such as a solar cell, for example, is stored in a capacitor or a battery. The power stored in the capacitor, the battery or the like may be used when executing a process (a task) that consumes a large amount of power, for example.
Conventionally, there are known various techniques of suppressing as much as possible consumption of power stored in the capacitor, the battery or the like. For example, regarding a mobile phone terminal, there is known, a technique of delaying execution of a task (for example, a download operation of an audio file) that consumes a large amount of power may be delayed until the terminal is connected to a charging device.
In a situation where a solar cell is generating power when a power storage device such as a capacitor or a battery capable of storing power generated by the solar cell is nearly fully charged, for example, surplus power may not be able to be stored in the power storage device, and the surplus power is wasted. There is no conventional technique of effectively using the surplus power in the situation as described above without wastefully discarding the surplus power.